From the Guidelines
Fetal Graves' disease is a condition that occurs when thyroid-stimulating antibodies from a mother with Graves' disease cross the placenta and stimulate the fetal thyroid, and its treatment primarily involves managing the mother's thyroid condition with antithyroid medications. The signs of fetal Graves' disease include fetal tachycardia (heart rate >160 beats per minute), intrauterine growth restriction, advanced bone age, goiter (enlarged thyroid visible on ultrasound), and sometimes heart failure or hydrops fetalis 1. Treatment of fetal Graves' disease involves the use of antithyroid medications, such as propylthiouracil (PTU) in the first trimester (50-300 mg daily in divided doses) and methimazole (5-30 mg daily) in the second and third trimesters, with the goal of maintaining maternal thyroid hormone levels in the high-normal range to minimize fetal exposure while preventing hypothyroidism 1. Some key points to consider in the treatment of fetal Graves' disease include:
- Regular fetal ultrasound monitoring every 2-4 weeks to assess thyroid size, growth, and heart rate
- Direct fetal therapy may be necessary through intra-amniotic injections of levothyroxine in severe cases with persistent fetal tachycardia or goiter despite maternal treatment
- A multidisciplinary approach involving maternal-fetal medicine specialists, endocrinologists, and neonatologists is necessary, as the newborn will need immediate evaluation after birth for thyroid dysfunction that may persist for several months 1. It is also important to note that thyroidectomy should be reserved for women who do not respond to thioamide therapy, and treatment with iodine 131 (I-131) is contraindicated in pregnant women 1. Overall, the treatment of fetal Graves' disease requires careful management and monitoring to minimize the risks of morbidity, mortality, and long-term complications for both the mother and the fetus.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Signs of Fetal Graves' Disease
- Tachycardia 2
- Goiter 3, 2, 4, 5
- Growth restriction 2, 5
- Advanced bone maturation 2
- Cardiomegaly 2
- Fetal death 2
- Fetal cardiac failure 2
Treatment of Fetal Graves' Disease
- Intrauterine therapy with levothyroxine 3
- Potassium iodine and propylthiouracil 2
- Reduction of maternal propylthiouracil (PTU) dosage 4, 5
- Weekly or biweekly therapeutic intervention schedule 3
- Monitoring of fetal thyroid goiter volume and amniotic fluid hormone levels to assess therapy efficacy 3
- Non-invasive management by reducing maternal PTU dosage and monitoring fetal thyroid function 5
- Maternal treatment with antithyroid drugs, such as methimazole and propylthiouracil (PTU) 3, 6